Mosquitoes utilize a variety of strategies to combat pathogens, including viruses. The long-term goal of the PIs research is to elucidate, at the molecular level, the immune responses of the mosquito vector Aedes aegypti to infection with a range of viral pathogens, including those that could be used as agents for bioterrorism. In recent years, dengue fever has emerged as one of the most serious vector-borne viral diseases. The molecular biology of dengue virus propagation in the mosquito vector is largely unknown, but the genome sequence, reverse genetic, transgenic and functional genomics tools that are now available provide a means of dissecting the mosquito's anti-viral defense systems in greater detail. In this proposal, we will apply these tools to characterize the implication of the Ae. aegypti JAK-STAT innate immune pathway in defense against the dengue virus. We have already showed that the mosquito is employing the JAK-STAT immune pathways to limit dengue virus infection through RNAi - based approaches. We will now use more powerful approaches, based on transgenic methodology, to expand on this finding and better characterize the JAK-STAT pathway immune responses to virus infection at multiple time points and tissues. In Specific Aim 1 we will generate and molecularly characterize the genetically modified mosquito lines that conditionally activate the JAK-STAT pathway. In Specific Aim 2 we will investigate the spatio- temporal anti-dengue activity of the recombinantly activated JAK-STAT pathway to better assess the potential use of this defense system for the development of dengue control strategies. PUBLIC HEALTH RELEVANCE: Despite the dramatic surge in dengue prevalence, surprisingly little is known about the molecular biology and genetic basis of the virus interactions with the mosquito vectors that enable transmission. This research proposal aims at the molecular characterization of the mosquito's immune defenses against virus infection that are controlled by the JAK-STAT pathway using transgenic technologies. The knowledge generated from this study can contribute to the development of control methods for dengue and other viruses such as yellow fever and West Niles viruses.